Staging
v0.7.0
v0.7.0
drm_debugfs_crc.c
/*
* Copyright © 2008 Intel Corporation
* Copyright © 2016 Collabora Ltd
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
* Based on code from the i915 driver.
* Original author: Damien Lespiau <damien.lespiau@intel.com>
*
*/
#include <linux/circ_buf.h>
#include <linux/ctype.h>
#include <linux/debugfs.h>
#include <linux/poll.h>
#include <linux/uaccess.h>
#include <drm/drm_crtc.h>
#include <drm/drm_debugfs_crc.h>
#include <drm/drm_drv.h>
#include <drm/drm_print.h>
#include "drm_internal.h"
/**
* DOC: CRC ABI
*
* DRM device drivers can provide to userspace CRC information of each frame as
* it reached a given hardware component (a CRC sampling "source").
*
* Userspace can control generation of CRCs in a given CRTC by writing to the
* file dri/0/crtc-N/crc/control in debugfs, with N being the index of the CRTC.
* Accepted values are source names (which are driver-specific) and the "auto"
* keyword, which will let the driver select a default source of frame CRCs
* for this CRTC.
*
* Once frame CRC generation is enabled, userspace can capture them by reading
* the dri/0/crtc-N/crc/data file. Each line in that file contains the frame
* number in the first field and then a number of unsigned integer fields
* containing the CRC data. Fields are separated by a single space and the number
* of CRC fields is source-specific.
*
* Note that though in some cases the CRC is computed in a specified way and on
* the frame contents as supplied by userspace (eDP 1.3), in general the CRC
* computation is performed in an unspecified way and on frame contents that have
* been already processed in also an unspecified way and thus userspace cannot
* rely on being able to generate matching CRC values for the frame contents that
* it submits. In this general case, the maximum userspace can do is to compare
* the reported CRCs of frames that should have the same contents.
*
* On the driver side the implementation effort is minimal, drivers only need to
* implement &drm_crtc_funcs.set_crc_source and &drm_crtc_funcs.verify_crc_source.
* The debugfs files are automatically set up if those vfuncs are set. CRC samples
* need to be captured in the driver by calling drm_crtc_add_crc_entry().
* Depending on the driver and HW requirements, &drm_crtc_funcs.set_crc_source
* may result in a commit (even a full modeset).
*
* CRC results must be reliable across non-full-modeset atomic commits, so if a
* commit via DRM_IOCTL_MODE_ATOMIC would disable or otherwise interfere with
* CRC generation, then the driver must mark that commit as a full modeset
* (drm_atomic_crtc_needs_modeset() should return true). As a result, to ensure
* consistent results, generic userspace must re-setup CRC generation after a
* legacy SETCRTC or an atomic commit with DRM_MODE_ATOMIC_ALLOW_MODESET.
*/
static int crc_control_show(struct seq_file *m, void *data)
{
struct drm_crtc *crtc = m->private;
if (crtc->funcs->get_crc_sources) {
size_t count;
const char *const *sources = crtc->funcs->get_crc_sources(crtc,
&count);
size_t values_cnt;
int i;
if (count == 0 || !sources)
goto out;
for (i = 0; i < count; i++)
if (!crtc->funcs->verify_crc_source(crtc, sources[i],
&values_cnt)) {
if (strcmp(sources[i], crtc->crc.source))
seq_printf(m, "%s\n", sources[i]);
else
seq_printf(m, "%s*\n", sources[i]);
}
}
return 0;
out:
seq_printf(m, "%s*\n", crtc->crc.source);
return 0;
}
static int crc_control_open(struct inode *inode, struct file *file)
{
struct drm_crtc *crtc = inode->i_private;
return single_open(file, crc_control_show, crtc);
}
static ssize_t crc_control_write(struct file *file, const char __user *ubuf,
size_t len, loff_t *offp)
{
struct seq_file *m = file->private_data;
struct drm_crtc *crtc = m->private;
struct drm_crtc_crc *crc = &crtc->crc;
char *source;
size_t values_cnt;
int ret;
if (len == 0)
return 0;
if (len > PAGE_SIZE - 1) {
DRM_DEBUG_KMS("Expected < %lu bytes into crtc crc control\n",
PAGE_SIZE);
return -E2BIG;
}
source = memdup_user_nul(ubuf, len);
if (IS_ERR(source))
return PTR_ERR(source);
if (source[len - 1] == '\n')
source[len - 1] = '\0';
ret = crtc->funcs->verify_crc_source(crtc, source, &values_cnt);
if (ret) {
kfree(source);
return ret;
}
spin_lock_irq(&crc->lock);
if (crc->opened) {
spin_unlock_irq(&crc->lock);
kfree(source);
return -EBUSY;
}
kfree(crc->source);
crc->source = source;
spin_unlock_irq(&crc->lock);
*offp += len;
return len;
}
static const struct file_operations drm_crtc_crc_control_fops = {
.owner = THIS_MODULE,
.open = crc_control_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
.write = crc_control_write
};
static int crtc_crc_data_count(struct drm_crtc_crc *crc)
{
assert_spin_locked(&crc->lock);
return CIRC_CNT(crc->head, crc->tail, DRM_CRC_ENTRIES_NR);
}
static void crtc_crc_cleanup(struct drm_crtc_crc *crc)
{
kfree(crc->entries);
crc->overflow = false;
crc->entries = NULL;
crc->head = 0;
crc->tail = 0;
crc->values_cnt = 0;
crc->opened = false;
}
static int crtc_crc_open(struct inode *inode, struct file *filep)
{
struct drm_crtc *crtc = inode->i_private;
struct drm_crtc_crc *crc = &crtc->crc;
struct drm_crtc_crc_entry *entries = NULL;
size_t values_cnt;
int ret = 0;
if (drm_drv_uses_atomic_modeset(crtc->dev)) {
ret = drm_modeset_lock_single_interruptible(&crtc->mutex);
if (ret)
return ret;
if (!crtc->state->active)
ret = -EIO;
drm_modeset_unlock(&crtc->mutex);
if (ret)
return ret;
}
ret = crtc->funcs->verify_crc_source(crtc, crc->source, &values_cnt);
if (ret)
return ret;
if (WARN_ON(values_cnt > DRM_MAX_CRC_NR))
return -EINVAL;
if (WARN_ON(values_cnt == 0))
return -EINVAL;
entries = kcalloc(DRM_CRC_ENTRIES_NR, sizeof(*entries), GFP_KERNEL);
if (!entries)
return -ENOMEM;
spin_lock_irq(&crc->lock);
if (!crc->opened) {
crc->opened = true;
crc->entries = entries;
crc->values_cnt = values_cnt;
} else {
ret = -EBUSY;
}
spin_unlock_irq(&crc->lock);
if (ret) {
kfree(entries);
return ret;
}
ret = crtc->funcs->set_crc_source(crtc, crc->source);
if (ret)
goto err;
return 0;
err:
spin_lock_irq(&crc->lock);
crtc_crc_cleanup(crc);
spin_unlock_irq(&crc->lock);
return ret;
}
static int crtc_crc_release(struct inode *inode, struct file *filep)
{
struct drm_crtc *crtc = filep->f_inode->i_private;
struct drm_crtc_crc *crc = &crtc->crc;
/* terminate the infinite while loop if 'drm_dp_aux_crc_work' running */
spin_lock_irq(&crc->lock);
crc->opened = false;
spin_unlock_irq(&crc->lock);
crtc->funcs->set_crc_source(crtc, NULL);
spin_lock_irq(&crc->lock);
crtc_crc_cleanup(crc);
spin_unlock_irq(&crc->lock);
return 0;
}
/*
* 1 frame field of 10 chars plus a number of CRC fields of 10 chars each, space
* separated, with a newline at the end and null-terminated.
*/
#define LINE_LEN(values_cnt) (10 + 11 * values_cnt + 1 + 1)
#define MAX_LINE_LEN (LINE_LEN(DRM_MAX_CRC_NR))
static ssize_t crtc_crc_read(struct file *filep, char __user *user_buf,
size_t count, loff_t *pos)
{
struct drm_crtc *crtc = filep->f_inode->i_private;
struct drm_crtc_crc *crc = &crtc->crc;
struct drm_crtc_crc_entry *entry;
char buf[MAX_LINE_LEN];
int ret, i;
spin_lock_irq(&crc->lock);
if (!crc->source) {
spin_unlock_irq(&crc->lock);
return 0;
}
/* Nothing to read? */
while (crtc_crc_data_count(crc) == 0) {
if (filep->f_flags & O_NONBLOCK) {
spin_unlock_irq(&crc->lock);
return -EAGAIN;
}
ret = wait_event_interruptible_lock_irq(crc->wq,
crtc_crc_data_count(crc),
crc->lock);
if (ret) {
spin_unlock_irq(&crc->lock);
return ret;
}
}
/* We know we have an entry to be read */
entry = &crc->entries[crc->tail];
if (count < LINE_LEN(crc->values_cnt)) {
spin_unlock_irq(&crc->lock);
return -EINVAL;
}
BUILD_BUG_ON_NOT_POWER_OF_2(DRM_CRC_ENTRIES_NR);
crc->tail = (crc->tail + 1) & (DRM_CRC_ENTRIES_NR - 1);
spin_unlock_irq(&crc->lock);
if (entry->has_frame_counter)
sprintf(buf, "0x%08x", entry->frame);
else
sprintf(buf, "XXXXXXXXXX");
for (i = 0; i < crc->values_cnt; i++)
sprintf(buf + 10 + i * 11, " 0x%08x", entry->crcs[i]);
sprintf(buf + 10 + crc->values_cnt * 11, "\n");
if (copy_to_user(user_buf, buf, LINE_LEN(crc->values_cnt)))
return -EFAULT;
return LINE_LEN(crc->values_cnt);
}
static __poll_t crtc_crc_poll(struct file *file, poll_table *wait)
{
struct drm_crtc *crtc = file->f_inode->i_private;
struct drm_crtc_crc *crc = &crtc->crc;
__poll_t ret = 0;
poll_wait(file, &crc->wq, wait);
spin_lock_irq(&crc->lock);
if (crc->source && crtc_crc_data_count(crc))
ret |= EPOLLIN | EPOLLRDNORM;
spin_unlock_irq(&crc->lock);
return ret;
}
static const struct file_operations drm_crtc_crc_data_fops = {
.owner = THIS_MODULE,
.open = crtc_crc_open,
.read = crtc_crc_read,
.poll = crtc_crc_poll,
.release = crtc_crc_release,
};
void drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
{
struct dentry *crc_ent;
if (!crtc->funcs->set_crc_source || !crtc->funcs->verify_crc_source)
return;
crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry);
debugfs_create_file("control", S_IRUGO | S_IWUSR, crc_ent, crtc,
&drm_crtc_crc_control_fops);
debugfs_create_file("data", S_IRUGO, crc_ent, crtc,
&drm_crtc_crc_data_fops);
}
/**
* drm_crtc_add_crc_entry - Add entry with CRC information for a frame
* @crtc: CRTC to which the frame belongs
* @has_frame: whether this entry has a frame number to go with
* @frame: number of the frame these CRCs are about
* @crcs: array of CRC values, with length matching #drm_crtc_crc.values_cnt
*
* For each frame, the driver polls the source of CRCs for new data and calls
* this function to add them to the buffer from where userspace reads.
*/
int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
uint32_t frame, uint32_t *crcs)
{
struct drm_crtc_crc *crc = &crtc->crc;
struct drm_crtc_crc_entry *entry;
int head, tail;
unsigned long flags;
spin_lock_irqsave(&crc->lock, flags);
/* Caller may not have noticed yet that userspace has stopped reading */
if (!crc->entries) {
spin_unlock_irqrestore(&crc->lock, flags);
return -EINVAL;
}
head = crc->head;
tail = crc->tail;
if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) {
bool was_overflow = crc->overflow;
crc->overflow = true;
spin_unlock_irqrestore(&crc->lock, flags);
if (!was_overflow)
DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n");
return -ENOBUFS;
}
entry = &crc->entries[head];
entry->frame = frame;
entry->has_frame_counter = has_frame;
memcpy(&entry->crcs, crcs, sizeof(*crcs) * crc->values_cnt);
head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1);
crc->head = head;
spin_unlock_irqrestore(&crc->lock, flags);
wake_up_interruptible(&crc->wq);
return 0;
}
EXPORT_SYMBOL_GPL(drm_crtc_add_crc_entry);